An Observational Study of Intramonthly Quasi-Periodicities in the Northern Heimsphere, Extratropical Geopotential Height Field

本研究旨在探讨北半球温带冷季对流层位势高度的10-30天准周期现象。从实验、理论和观测的角度来看，对这种现象的探索是合理的。他们将以理论为指导进行审查。将利用各种统计技术来评估这些现象的重要性和量化它们的重要性。与大多数其他此类研究不同，这些现象的非平稳性将直接纳入分析和显著性检验。此外，这些分析将考虑到地域性，并将基于比以往大多数此类研究大得多的样本。本研究将使用旋转复主成分（RCPC's）。RCPC分析技术是一种强大的统计工具，最近才被介绍给气象学家。这种方法和几种更简单的方法将产生振幅和相位的时间序列。统计检验将主要在这些时间序列上进行。研究结果应展望10 ~ 30天对流层高度变化的各个方面，包括准周期现象的规律性、持续时间以及与准平稳状态的关系。这项研究很重要，因为它对一组长期、高质量的大气环流观测资料进行了严格的统计分析，以寻求季节内振荡对气候特征重要性的问题的答案。

This research is aimed at investigating 10-30 day quasi- periodic phenomena in the extratropical, cold season tropospheric geopotential heights of the Northern Hemisphere. The search for such phenomena is justified on experimental, theoretical and observational grounds. They will be examined using theory as guidance. A variety of statistical techniques will be utilized in order to assess the significance and quantify the importance of such phenomena. Unlike most other studies of this type the non-stationarity of these phenomena will be incorporated directly into the analyses and significance testing. Also, the analyses will allow for regionality and will be based on a much larger sample than most prior studies of this nature. Rotated complex principal components (RCPC's) will be used in this study. The RCPC analysis technique, which is a powerful statistical tool, has been introduced to meteorologists only very recently. This and several simpler approaches will yield time series of amplitude and phase. The statistical tests will be performed primarily on these time series. The results of this study should put into prospective various aspects of the variability of tropospheric heights in the 10-30 day range, including regularity, duration and relation of the quasi-periodic phenomena to the quasi-stationary state. This research is important because it applies rigorous statistical analysis to a long-term, high quality set of atmospheric circulation observations to seek answers to the question of the importance of intraseasonal oscillations on climate characteristics.